Heat exchanger and refrigeration cycle apparatus

ABSTRACT

A heat exchanger includes: a fin extending in a widthwise direction along an air flow direction and extending in a longitudinal direction crossing the air flow direction; and a heat transfer tube passing through the fin. The fin includes a planar portion, and a plurality of first protruding portions and a plurality of second protruding portions that protrude from the planar portion. The plurality of first protruding portions include a first projection curved downward in the longitudinal direction, and a second projection curved upward in the longitudinal direction. Each of the plurality of second protruding portions surrounds a corresponding one of the plurality of through holes. A vertex of the first projection and a vertex of the second projection are located at the same position in the widthwise direction.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger and a refrigerationcycle apparatus.

BACKGROUND ART

Conventionally, there has been a fin-and-tube-type heat exchangerincluding a fin and a heat transfer tube passing through the fin. Forexample, in a heat exchanger described in Japanese Patent Laying-OpenNo. 2005-77083 (PTL 1), a fin includes a seat portion (planar portion),and peak and valley portions. The seat portion is concentrically formedaround an outer circumference of a fin collar to guide air flowingaround a heat transfer tube to thereby reduce a wake region. The seatportion is provided with opened front and rear portions. The peak andvalley portions are continuously formed between the fin collars toprovide airflow variation.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Laying-Open No. 2005-77083

SUMMARY OF INVENTION Technical Problem

In the heat exchanger described in the literature above, the peak andvalley portions are continuously formed along an air flow direction, andthus, a boundary layer starting from the peak portion is formed.Therefore, the valley portion forms a dead water region. As a result, alocal heat transfer coefficient in the valley portion decreases, whichleads to a decrease in heat transfer coefficient of the entire fin. Inaddition, stress concentrates on the planar portion provided with nopeak and valley portions, and thus, the fin has insufficient strength.Furthermore, the water adhering to the fin is hindered from beingdischarged along a longitudinal direction of the fin.

The present disclosure has been made in view of the above-describedproblem, and an object thereof is to provide a heat exchanger and arefrigeration cycle apparatus that can achieve improvements in heattransfer efficiency, strength of a fin, and drainage performance of thewater adhering to the fin.

Solution to Problem

A heat exchanger of the present disclosure includes: a fin extending ina widthwise direction along an air flow direction and extending in alongitudinal direction crossing the air flow direction; and a heattransfer tube passing through the fin. The fin has a plurality ofthrough holes arranged in the longitudinal direction. The heat transfertube is inserted in the plurality of through holes. The fin includes aplanar portion, and a plurality of first protruding portions and aplurality of second protruding portions that protrude from the planarportion. The plurality of first protruding portions include a firstprojection located between corresponding through holes of the pluralityof through holes and curved downward in the longitudinal direction, anda second projection located between corresponding through holes of theplurality of through holes and curved upward in the longitudinaldirection. Each of the plurality of second protruding portions islocated between a corresponding one of the plurality of first protrudingportions and a corresponding one of the plurality of through holes, andsurrounding the corresponding through hole. A vertex of the firstprojection and a vertex of the second projection are located at the sameposition in the widthwise direction.

Advantageous Effects of Invention

According to the heat exchanger of the present disclosure, the firstprotruding portions and the second protruding portions protrude from theplanar portion, and thus, an influence of a dead water region can besuppressed. Therefore, an improvement in heat transfer coefficient ofthe fin can be achieved. In addition, an improvement in strength of thefin can be achieved by the first protruding portions and the secondprotruding portions. Furthermore, since the vertex of the firstprojection and the vertex of the second projection are located at thesame position in the widthwise direction, an improvement in drainageperformance can be achieved by guiding the water flown from the vertexof the first projection through the vertex of the second projection toboth sides.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view schematically showing a configuration of aheat exchanger according to a first embodiment.

FIG. 2 is a cross-sectional view of a region A in FIG. 1 taken alongline II-II.

FIG. 3 is an end view taken along line in FIG. 2 .

FIG. 4 is an end view taken along line IV-IV in FIG. 2 .

FIG. 5 is a refrigerant circuit diagram showing a refrigeration cycleapparatus according to the first embodiment.

FIG. 6 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a second embodimentcorresponding to FIG. 2 .

FIG. 7 is an end view taken along line VII-VII in FIG. 6 .

FIG. 8 is an end view taken along line VIII-VIII in FIG. 6 .

FIG. 9 is an enlarged view of an IX portion in FIG. 8 .

FIG. 10 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a third embodimentcorresponding to FIG. 2 .

FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10 .

FIG. 12 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a fourth embodimentcorresponding to FIG. 2 .

FIG. 13 is an end view taken along line XIII-XIII in FIG. 12 .

FIG. 14 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a fifth embodimentcorresponding to FIG. 2 .

FIG. 15 is an end view taken along line XV-XV in FIG. 14 .

FIG. 16 is an end view taken along line XVI-XVI in FIG. 14 .

FIG. 17 is a cross-sectional view schematically showing a configurationof a portion of a heat exchanger according to a sixth embodimentcorresponding to FIG. 2 .

FIG. 18 is an end view taken along line XVIII-XVIII in FIG. 17 .

FIG. 19 is an end view taken along line XIX-XIX in FIG. 17 .

DESCRIPTION OF EMBODIMENTS

Embodiments will be described hereinafter with reference to thedrawings. In the following description, the same or correspondingportions are denoted by the same reference characters and descriptionthereof will not be repeated.

First Embodiment

A configuration of a heat exchanger HE according to a first embodimentwill be described with reference to FIGS. 1 to 4 .

Referring to FIGS. 1 and 2 , heat exchanger HE includes a fin F and aheat transfer tube P. Fin F extends in a widthwise direction D1 along anair flow direction D0 and extends in a longitudinal direction D2crossing air flow direction DO. Fin F is formed in a substantiallyrectangular shape. Heat transfer tube P passes through fin F. Heattransfer tube P is a circular pipe. Fin F has a plurality of throughholes TH arranged in longitudinal direction D2. Each of the plurality ofthrough holes TH is formed to have a circular shape. Heat transfer tubeP is inserted in the plurality of through holes TH.

In the present embodiment, heat exchanger HE includes a plurality offins F. The plurality of fins F are stacked on top of each other atintervals. Heat transfer tube P passes through the plurality of fins Fin a direction D3 of stacking of the plurality of fins F. Each of theplurality of fins F has a plurality of through holes TH. The pluralityof through holes TH are arranged in longitudinal direction D2 of fin F.The plurality of through holes TH are spaced apart from each other inlongitudinal direction D2 of fin F.

Widthwise direction D1 of fin F is orthogonal to longitudinal directionD2. Widthwise direction D1 of fin F may be a horizontal direction.Longitudinal direction D2 of fin F may be an up-down direction (verticaldirection). Direction D3 of stacking of fins F is orthogonal towidthwise direction D1 and longitudinal direction D2 of fin F.

Heat transfer tube P includes a plurality of heat transfer portions P1and a plurality of connection portions P2. Each of the plurality of heattransfer portions P1 passes through the plurality of fins F. Each of theplurality of heat transfer portions P1 is inserted in the plurality ofthrough holes TH in direction D3 of stacking of the plurality of fins F.The plurality of heat transfer portions P1 are formed linearly. Each ofthe plurality of heat transfer portions P1 extends in direction D3 ofstacking of the plurality of fins F.

Each of the plurality of connection portions P2 is a portion thatconnects corresponding heat transfer portions P1 of the plurality ofheat transfer portions P1 outside the plurality of fins F. Each of theplurality of connection portions P2 is formed to have a U shape. Each ofthe plurality of connection portions P2 connects heat transfer tubes Pthat are adjacent to each other in longitudinal direction D2 of fins F.Each of the plurality of connection portions P2 is connected to ends ofheat transfer portions P1 in direction D3 of stacking of the pluralityof fins F. The plurality of heat transfer portions P1 are disposed inmultiple stages in longitudinal direction D2 of fins F. In the presentembodiment, the plurality of heat transfer portions P1 are disposed infour stages along longitudinal direction D2 of fins F.

The plurality of heat transfer portions P1 are connected by theplurality of connection portions P2 as follows. Heat transfer portion P1in the first stage is connected to heat transfer portion P1 in thesecond stage by connection portion P2 on the back side in direction D3of stacking of the plurality of fins F. Heat transfer portion P1 in thesecond stage is connected to heat transfer portion P1 in the third stageby connection portion P2 on the front side in direction D3 of stackingof the plurality of fins F. Heat transfer portion P1 in the third stageis connected to heat transfer portion P1 in the fourth stage byconnection portion P2 on the back side in direction D3 of stacking ofthe plurality of fins F. In this way, heat transfer tube P is configuredto meander in longitudinal direction D2 of fins F.

A structure of fin F will be described in detail with reference to FIGS.2 to 4 .

Fin F includes a planar portion SP, a plurality of first protrudingportions MP1, a plurality of second protruding portions MP2, and a fincollar FC. Planar portion SP is formed in a planar shape. Planar portionSP is formed in a flat plate shape.

The plurality of first protruding portions MP1 and the plurality ofsecond protruding portions MP2 protrude from planar portion SP. In thepresent embodiment, the plurality of first protruding portions MP1 andthe plurality of second protruding portions MP2 protrude from planarportion SP in the same direction.

The plurality of first protruding portions MP1 include a firstprojection C1 and a second projection C2. First projection C1 is locatedbetween corresponding through holes TH of the plurality of through holesTH. First projection C1 is located below a corresponding one of theplurality of through holes TH. First projection C1 is curved downward inlongitudinal direction D2 of fin F. Second projection C2 is locatedbetween corresponding through holes TH of the plurality of through holesTH. Second projection C2 is located above a corresponding one of theplurality of through holes TH. Second projection C2 is curved upward inlongitudinal direction D2 of fin F. In the present embodiment, theplurality of first protruding portions MP1 include a plurality of firstprojections C1 and a plurality of second projections C2.

First protruding portion MP1 has a portion extending along longitudinaldirection D2 of fin F. First protruding portion MP1 also has a portionextending along widthwise direction D1 of fin F. First protrudingportion MP1 is located to be displaced from a center of through hole THin widthwise direction D1 of fin F. In the present embodiment, firstprotruding portion MP1 is formed to have an arc shape. In the presentembodiment, widths of first protruding portions MP1 are equal to eachother.

The plurality of first protruding portions MP1 are arranged inlongitudinal direction D2 of fin F. In the present embodiment, fourfirst protruding portions MP1 are located between two through holes THin longitudinal direction D2 of fin F. Two first protruding portions MP1are located on each of the upper side and the lower side of one throughhole TH in longitudinal direction D2 of fin F.

Two first projections C1 located on the lower side of one through holeTH in longitudinal direction D2 of fin F are located to be adjacent toeach other in longitudinal direction D2 of fin F. Two second projectionsC2 located on the upper side of one through hole TH in longitudinaldirection D2 of fin F are located to be adjacent to each other inlongitudinal direction D2 of fin F.

Two first projections C1 located to be adjacent to each other are curvedtoward the same side along longitudinal direction D2. Two secondprojections C2 located to be adjacent to each other are curved towardthe side opposite to two first projections C1 along longitudinaldirection D2.

Two first projections C1 located near upper-side through hole TH of twothrough holes TH are curved to protrude toward the lower side. Twosecond projections C2 located near lower-side through hole TH of twothrough holes TH are curved to protrude toward the upper side.Outer-side first projection C1, of two first projections C1 curved toprotrude toward the lower side, is spaced apart from outer-side secondprojection C2, of two second projections C2 curved to protrude towardthe upper side.

The plurality of first projections C1 are formed to have the same shape.Curvature radii of the plurality of first projections C1 are equal toeach other. Centers of curvature of the plurality of first projectionsC1 are arranged in line with each other in longitudinal direction D2 offin F. Widths of the plurality of first projections C1 are equal to eachother. Lengths of the plurality of first projections C1 are equal toeach other.

Each of the plurality of first projections C1 is formed to have the sameshape as that of each of the plurality of second projections C2, excepta direction of curving along longitudinal direction D2 of fin F. Theplurality of second projections C2 are formed to have the same shape.Curvature radii of the plurality of second projections C2 are equal toeach other. Centers of curvature of the plurality of second projectionsC2 are arranged in line with each other in longitudinal direction D2 offin F. Widths of the plurality of second projections C2 are equal toeach other. Lengths of the plurality of second projections C2 are equalto each other.

Each of the plurality of first protruding portions MP1 is longer thaneach of the plurality of second protruding portions MP2 in widthwisedirection D1 of fin F. In longitudinal direction D2 of fin F, each ofthe plurality of first protruding portions MP1 is located betweencorresponding ones of the plurality of second protruding portions MP2.The respective centers of curvature of the plurality of first protrudingportions MP1 are arranged in line with the respective centers of theplurality of second protruding portions MP2 in longitudinal direction D2of fin F.

Inner-side first protruding portion MP1, of two first protrudingportions MP1 located on the upper side of through hole TH inlongitudinal direction D2 of fin F, is adjacent to second protrudingportion MP2. Inner-side first protruding portion MP1, of two firstprotruding portions MP1 located on the lower side of through hole TH inlongitudinal direction D2 of fin F, is adjacent to second protrudingportion MP2.

Each of the plurality of second protruding portions MP2 is locatedbetween a corresponding one of first protruding portions MP1 and acorresponding one of the plurality of through holes TH. Each of theplurality of second protruding portions MP2 surrounds the correspondingone of the plurality of through holes TH. Second protruding portion MP2is formed to have an annular shape. Second protruding portion MP2protrudes from planar portion SP more than first protruding portion MP1.

The plurality of second protruding portions MP2 are formed to have thesame shape. The respective centers of the plurality of second protrudingportions MP2 are arranged in line in longitudinal direction D2 of fin F.The plurality of second protruding portions MP2 have the same shape. Theplurality of second protruding portions MP2 have the same diameter.

A vertex V of first projection C1 and a vertex V of second projection C2are located at the same position in widthwise direction D1 of fin F.Vertexes V of first projection C1 and second projection C2 are portionsthat protrude most along longitudinal direction D2 of fin F. Vertex V offirst projection C1 and vertex V of second projection C2 are arranged inline in longitudinal direction D2 of fin F.

First protruding portion MP1 is narrower in width than second protrudingportion MP2. That is, the width of each of the plurality of firstprotruding portions MP1 is narrower than the width of each of theplurality of second protruding portions MP2.

A top of a protrusion of first protruding portion MP1 is located at acenter of the width of first protruding portion MP1. A top of aprotrusion of second protruding portion MP2 is located at a center ofthe width of second protruding portion MP2.

First protruding portion MP1 and second protruding portion MP2 are lowerin protruding height from planar portion SP than fin collar FC.

Fin collar FC is formed to have a cylindrical shape. Heat transfer tubeP is inserted in fin collar FC. The outer circumferential surface ofheat transfer tube P fits onto the inner circumferential surface of fincollar FC. Fin collar FC protrudes from planar portion SP. In thepresent embodiment, fin collar FC protrudes from planar portion SP inthe same direction as that of first protruding portion MP1 and secondprotruding portion MP2.

Fin collar FC includes a circumferential wall and a flange. Thecircumferential wall protrudes from planar portion SP. The flangeextends outward from the circumferential wall. The flange is provided atthe edge of the circumferential wall opposite to planar portion SP. Inthe present embodiment, fin F includes a plurality of fin collars FC.

A configuration of a refrigeration cycle apparatus 100 including heatexchanger HE according to the first embodiment will be described withreference to FIG. 5 . Refrigeration cycle apparatus 100 is, for example,an air conditioner, a refrigerating machine and the like. In the firstembodiment, an air conditioner is described as an example ofrefrigeration cycle apparatus 100. Refrigeration cycle apparatus 100includes a refrigerant circuit RC, refrigerant, a controller CD, and airblowers 6 and 7. Refrigeration cycle apparatus 100 includes arefrigerant circulation device RCD. Refrigerant circulation device RCDis configured to circulate refrigerant for performing heat exchange withair in heat exchanger HE. In the first embodiment, refrigeration cycleapparatus 100 including a compressor 1 incorporated therein asrefrigerant circulation device RCD is described. Refrigerant circulationdevice RCD may be a refrigerant pump.

Refrigerant circuit RC includes compressor 1, a four-way valve 2, anoutdoor heat exchanger 3, a pressure reducing valve 4, and an indoorheat exchanger 5. Heat exchanger HE described above may be applied to atleast one of outdoor heat exchanger 3 and indoor heat exchanger 5.Compressor 1, four-way valve 2, outdoor heat exchanger 3, pressurereducing valve 4, and indoor heat exchanger 5 are connected by a pipe.Refrigerant circuit RC is configured to circulate the refrigerant.Refrigerant circuit RC is configured to perform a refrigeration cycle inwhich the refrigerant circulates while changing its phase.

Compressor 1, four-way valve 2, outdoor heat exchanger 3, pressurereducing valve 4, controller CD, and air blower 6 are housed in anoutdoor unit 101. Indoor heat exchanger 5 and air blower 7 are housed inan indoor unit 102.

Refrigerant circuit RC is configured such that the refrigerantcirculates in the order of compressor 1, four-way valve 2, outdoor heatexchanger (condenser) 3, pressure reducing valve 4, indoor heatexchanger (evaporator) 5, and four-way valve 2 during a coolingoperation. Refrigerant circuit RC is configured such that therefrigerant circulates in the order of compressor 1, four-way valve 2,indoor heat exchanger (condenser) 5, pressure reducing valve 4, outdoorheat exchanger (evaporator) 3, and four-way valve 2 during a heatingoperation.

The refrigerant flows through refrigerant circuit RC in the order ofcompressor 1, the condenser, pressure reducing valve 4, and theevaporator.

Controller CD is configured to control each device of refrigerationcycle apparatus 100 by, for example, performing calculations orproviding instructions. Controller CD is electrically connected tocompressor 1, four-way valve 2, pressure reducing valve 4, air blowers 6and 7, and the like to control the operations of these components.

Compressor 1 is configured to compress the refrigerant for performingheat exchange with the air in heat exchanger HE. Compressor 1 isconfigured to compress the sucked refrigerant and discharge thecompressed refrigerant. Compressor 1 may be configured to have avariable capacity. Compressor 1 may be configured to have a capacitychanging through the adjustment of the rotation speed of compressor 1based on an instruction provided from controller CD.

Four-way valve 2 is configured to switch a flow of the refrigerant suchthat the refrigerant compressed by compressor 1 flows to outdoor heatexchanger 3 or indoor heat exchanger 5. Four-way valve 2 is configuredsuch that during the cooling operation, the refrigerant discharged fromcompressor 1 flows to outdoor heat exchanger (condenser) 3. Four-wayvalve 2 is configured such that during the heating operation, therefrigerant discharged from compressor 1 flows to indoor heat exchanger(evaporator) 5.

Outdoor heat exchanger 3 is configured to exchange heat between therefrigerant flowing inside outdoor heat exchanger 3 and the air flowingoutside outdoor heat exchanger 3. Outdoor heat exchanger 3 is configuredto function as a condenser that condenses the refrigerant during thecooling operation, and function as an evaporator that evaporates therefrigerant during the heating operation.

Pressure reducing valve 4 is configured to reduce pressure by expandingthe refrigerant condensed by the condenser. Pressure reducing valve 4 isconfigured to reduce the pressure of the refrigerant condensed byoutdoor heat exchanger (condenser) 3 during the cooling operation, andreduce the pressure of the refrigerant condensed by indoor heatexchanger (evaporator) 5 during the heating operation. Pressure reducingvalve 4 is, for example, a solenoid valve.

Indoor heat exchanger 5 is configured to exchange heat between therefrigerant flowing inside indoor heat exchanger 5 and the air flowingoutside indoor heat exchanger 5. Indoor heat exchanger 5 is configuredto function as an evaporator that evaporates the refrigerant during thecooling operation, and function as a condenser that condenses therefrigerant during the heating operation.

Air blower 6 is configured to blow the outdoor air to outdoor heatexchanger 3. That is, air blower 6 is configured to supply the air tooutdoor heat exchanger 3. Air blower 6 may be configured to adjust theamount of heat exchange between the refrigerant and the air by adjustinga rotation speed of air blower 6 based on an instruction provided fromcontroller CD, thereby adjusting an amount of heat exchange between therefrigerant and the air.

Air blower 7 is configured to blow the indoor air to indoor heatexchanger 5. That is, air blower 7 is configured to supply the air toindoor heat exchanger 5. Air blower 7 may be configured to adjust theamount of the air flowing around indoor heat exchanger 5 through theadjustment of the rotation speed of air blower 7 based on an instructionprovided from controller CD, thereby adjusting an amount of heatexchange between the refrigerant and the air.

Next, the operation of refrigeration cycle apparatus 100 will bedescribed with reference to FIG. 5 . A solid arrow in FIG. 5 indicates aflow of the refrigerant during the cooling operation, and a dashed arrowin FIG. 5 indicates a flow of the refrigerant during the heatingoperation.

Refrigeration cycle apparatus 100 can selectively perform the coolingoperation and the heating operation. During the cooling operation, therefrigerant circulates in refrigerant circuit RC in the order ofcompressor 1, four-way valve 2, outdoor heat exchanger 3, pressurereducing valve 4, indoor heat exchanger 5, and four-way valve 2. Duringthe cooling operation, outdoor heat exchanger 3 functions as acondenser. Heat is exchanged between the refrigerant flowing throughoutdoor heat exchanger 3 and the air blown by air blower 6. During thecooling operation, indoor heat exchanger 5 functions as an evaporator.Heat is exchanged between the refrigerant flowing through indoor heatexchanger 5 and the air blown by air blower 7.

During the heating operation, the refrigerant circulates throughrefrigerant circuit RC in the order of compressor 1, four-way valve 2,indoor heat exchanger 5, pressure reducing valve 4, outdoor heatexchanger 3, and four-way valve 2. During the heating operation, indoorheat exchanger 5 functions as a condenser. Heat is exchanged between therefrigerant flowing through indoor heat exchanger 5 and the air blown byair blower 7. During the heating operation, outdoor heat exchanger 3functions as an evaporator. Heat is exchanged between the refrigerantflowing through outdoor heat exchanger 3 and the air blown by air blower6.

Refrigeration cycle apparatus 100 can also perform defrosting operation.During the defrosting operation, the refrigerant temporarily circulatesin refrigerant circuit RC in the same order as that during the coolingoperation. As a result, frost that formed on the evaporator is melted bythe heat of the refrigerant. In this way, the frost that formed on theevaporator is removed.

Next, a function and effect of the first embodiment will be described.

In heat exchanger HE according to the first embodiment, first protrudingportions MP1 and second protruding portions MP2 protrude from planarportion SP, and thus, an influence of a dead water region can besuppressed. Therefore, an improvement in heat transfer coefficient offin F can be achieved. In addition, an improvement in strength of fin Fcan be achieved by first protruding portions MP1 and second protrudingportions MP2. Furthermore, since vertex V of first projection C1 andvertex V of second projection C2 are located at the same position inwidthwise direction D1 of fin F, an improvement in drainage performancecan be achieved by guiding the water flown from vertex V of firstprojection C1 through vertex V of second projection C2 to both sides.This water may be condensed water, or may be defrosting water generatedduring defrosting.

In heat exchanger HE according to the first embodiment, first protrudingportion MP1 is narrower in width than second protruding portion MP2.Therefore, by guiding the water accumulated in second protruding portionMP2 to first protruding portion MP1 due to surface tension, animprovement in drainage performance can be achieved.

Second Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a second embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thefirst embodiment.

A structure of fin F of heat exchanger HE according to the secondembodiment will be described with reference to FIGS. 6 to 9 .

As shown in FIGS. 6 to 8 , in the present embodiment, a top of aprotrusion of first protruding portion MP1 is located outside a centerof a width of first protruding portion MP1. A top of a protrusion ofsecond protruding portion MP2 is located outside a center of a width ofsecond protruding portion MP2. In at least one of first protrudingportion MP1 and second protruding portion MP2, the top of the protrusionmay be located outside the center of the width.

As shown in FIGS. 8 and 9 , at least one of first protruding portion MP1and second protruding portion MP2 includes an inner inclined surface ISand an outer inclined surface OS. Inner inclined surface IS is locatedto face a corresponding one of the plurality of through holes TH. Outerinclined surface OS is located opposite to the corresponding one of theplurality of through holes with respect to inner inclined surface IS. Aninner inclination angle θ1 formed by inner inclined surface IS withrespect to planar portion SP is smaller than an outer inclination angleθ2 formed by outer inclined surface OS with respect to planar portionSP.

Next, the function and effect of the second embodiment will bedescribed.

In heat exchanger HE according to the second embodiment, innerinclination angle θ1 formed by inner inclined surface IS with respect toplanar portion SP is smaller than outer inclination angle θ2 formed byouter inclined surface OS with respect to planar portion SP. Therefore,accumulation of the water adhering to fin F in inner inclined surface IScan be suppressed. Therefore, an improvement in drainage performance canbe achieved.

Third Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a third embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thesecond embodiment.

A structure of fin F of heat exchanger HE according to the thirdembodiment will be described with reference to FIGS. 10 and 11 .

First protruding portion MP1 is inclined such that a protruding heightfrom planar portion SP becomes lower toward a center of first protrudingportion MP1 in widthwise direction D1 of fin F. Second protrudingportion MP2 is inclined such that a protruding height from planarportion SP becomes lower toward a center of second protruding portionMP2 in widthwise direction D1 of fin F.

At least one of first protruding portion MP1 and second protrudingportion MP2 may be inclined such that the protruding height from planarportion SP becomes lower toward the center of the at least one of firstprotruding portion MP1 and second protruding portion MP2 in widthwisedirection D1 of fin F.

Next, the function and effect of the third embodiment will be described.

In heat exchanger HE according to the third embodiment, at least one offirst protruding portion MP1 and second protruding portion MP2 isinclined such that the protruding height from planar portion SP becomeslower toward the center of the at least one of first protruding portionMP1 and second protruding portion MP2 in widthwise direction D1 of finF. Therefore, when the water adhering to fin F falls downward, hindranceof the fall of the water adhering to fin F in at least one of firstprotruding portion MP1 and second protruding portion MP2 can besuppressed. Therefore, an improvement in drainage performance can beachieved.

Fourth Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a fourth embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thesecond embodiment.

A structure of fin F of heat exchanger HE according to the fourthembodiment will be described with reference to FIGS. 12 and 13 .

Fin F includes an intermediate protruding portion MM. Intermediateprotruding portion MM protrudes from planar portion SP. Intermediateprotruding portion MM protrudes from planar portion SP in the samedirection as that of first protruding portion MP1 and second protrudingportion MP2.

Intermediate protruding portion MM extends linearly in longitudinaldirection D2 of fin F. Intermediate protruding portion MM connects thevertex of first projection C1 and the vertex of second projection C2.Intermediate protruding portion MM is narrower in width than firstprotruding portion MP1.

Next, the function and effect of the fourth embodiment will bedescribed.

In heat exchanger HE according to the fourth embodiment, intermediateprotruding portion MM connects the vertex of first projection C1 and thevertex of second projection C2. Therefore, intermediate protrudingportion MM functions as a drainage path, and thus, accumulation of thewater adhering to the fin in first protruding portion MP1 can besuppressed. Therefore, an improvement in drainage performance can beachieved.

Fifth Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a fifth embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thesecond embodiment.

A structure of fin F of heat exchanger HE according to the fifthembodiment will be described with reference to FIGS. 14 to 16 .

Fin F includes a third protruding portion MP3. Fin F protrudes fromplanar portion SP. Third protruding portion MP3 protrudes from planarportion SP in the same direction as that of first protruding portion MP1and second protruding portion MP2. Third protruding portion MP3 extendslinearly in longitudinal direction D2 of fin F. Third protruding portionMP3 extends continuously from one end to the other end in longitudinaldirection D2 of fin F.

Third protruding portion MP3 is located outside first protruding portionMP1 in widthwise direction D1 of fin F. Third protruding portion MP3 islocated outside second protruding portion MP2 in widthwise direction D1of fin F. Third protruding portion MP3 is narrower in width than firstprotruding portion MP1 and second protruding portion MP2.

In the present embodiment, fin F includes a plurality of thirdprotruding portions MP3. The plurality of third protruding portions MP3extend in parallel to each other in longitudinal direction D2 of fin F.The plurality of third protruding portions MP3 are located at both endsin widthwise direction D1 of fin F. The plurality of third protrudingportions MP3 are located to sandwich the plurality of first protrudingportions MP1 and the plurality of second protruding portions MP2. Thirdprotruding portions MP3 are spaced apart from first protruding portionsMP1 and second protruding portions MP2 in widthwise direction D1 of finF. Widths of the plurality of third protruding portions MP3 are equal toeach other.

Next, the function and effect of the fifth embodiment will be described.

In heat exchanger HE according to the fifth embodiment, third protrudingportion MP3 extends linearly in longitudinal direction D2 of fin F.Therefore, an improvement in strength of fin F in longitudinal directionD2 of fin F can be achieved by third protruding portion MP3.

Third protruding portion MP3 is located outside first protruding portionMP1 in widthwise direction D1 of fin F and is narrower in width thanfirst protruding portion MP1 and second protruding portion MP2.Therefore, the water adhering to fin F can be guided from firstprotruding portion MP1 to third protruding portion MP3 due to surfacetension. The water adhering to fin F can then flow along thirdprotruding portion MP3. Therefore, an improvement in drainageperformance can be achieved.

Sixth Embodiment

Unless otherwise specified, heat exchanger HE and refrigeration cycleapparatus 100 according to a sixth embodiment have the sameconfiguration, operation, and function and effect as those of heatexchanger HE and refrigeration cycle apparatus 100 according to thefifth embodiment.

A structure of fin F of heat exchanger HE according to the sixthembodiment will be described with reference to FIGS. 17 to 19 .

First projection C1 is located at a position that is more distant fromthird protruding portion MP3 than second projection C2 in widthwisedirection D1 of fin F. First projection C1 is shorter than secondprojection C2 in widthwise direction D1 of fin F.

Next, the function and effect of the sixth embodiment will be described.

In heat exchanger HE according to the sixth embodiment, first projectionC1 is located at a position that is more distant from third protrudingportion MP3 than second projection C2 in widthwise direction D1 of finF. Therefore, the water adhering to fin F is easily guided from secondprojection C2 to third protruding portion MP3. In addition, movement ofthe water adhering to fin F from third protruding portion MP3 to firstprojection C1 can be suppressed. Therefore, an improvement in drainageperformance can be achieved.

It should be understood that the embodiments disclosed herein areillustrative and non-restrictive in every respect. The scope of thepresent disclosure is defined by the terms of the claims, rather thanthe description above, and is intended to include any modificationswithin the scope and meaning equivalent to the terms of the claims.

REFERENCE SIGNS LIST

1 compressor; 2 four-way valve; 3 outdoor heat exchanger; 4 pressurereducing valve; 5 indoor heat exchanger; 100 refrigeration cycleapparatus; C1 first projection; C2 second projection; D0 air flowdirection; D1 widthwise direction; D2 longitudinal direction; F fin; HEheat exchanger; IS inner inclined surface; MP1 first protruding portion;MP2 second protruding portion; MP3 third protruding portion; OS outerinclined surface; P heat transfer tube; SP planar portion; TH throughhole; V vertex.

1. A heat exchanger comprising: a fin extending in a widthwise directionalong an air flow direction and extending in a longitudinal directioncrossing the air flow direction; and a heat transfer tube passingthrough the fin, the fin having a plurality of through holes arranged inthe longitudinal direction, the heat transfer tube being inserted in theplurality of through holes, the fin comprising a planar portion, and aplurality of first protruding portions and a plurality of secondprotruding portions that protrude from the planar portion, the pluralityof first protruding portions comprising a first projection locatedbetween corresponding through holes of the plurality of through holesand curved downward in the longitudinal direction, and a secondprojection located between corresponding through holes of the pluralityof through holes and curved upward in the longitudinal direction, eachof the plurality of second protruding portions being located between acorresponding one of the plurality of first protruding portions and acorresponding one of the plurality of through holes, and surrounding thecorresponding through hole, and a vertex of the first projection and avertex of the second projection being located at the same position inthe widthwise direction.
 2. The heat exchanger according to claim 1,wherein the first protruding portion is narrower in width than thesecond protruding portion.
 3. The heat exchanger according to claim 1,wherein at least one of the first protruding portion and the secondprotruding portion includes an inner inclined surface located to face acorresponding one of the plurality of through holes, and an outerinclined surface located opposite to the corresponding one of theplurality of through holes with respect to the inner inclined surface,and an inner inclination angle formed by the inner inclined surface withrespect to the planar portion is smaller than an outer inclination angleformed by the outer inclined surface with respect to the planar portion.4. The heat exchanger according to claim 3, wherein at least one of thefirst protruding portion and the second protruding portion is inclinedsuch that a protruding height from the planar portion becomes lowertoward a center of the at least one of the first protruding portion andthe second protruding portion in the widthwise direction.
 5. The heatexchanger according to claim 1, wherein the fin includes an intermediateprotruding portion protruding from the planar portion, and theintermediate protruding portion extends linearly in the longitudinaldirection and connects the vertex of the first projection and the vertexof the second projection.
 6. The heat exchanger according to claim 1,wherein the fin includes a third protruding portion protruding from theplanar portion, and the third protruding portion extends linearly in thelongitudinal direction.
 7. The heat exchanger according to claim 6,wherein the third protruding portion is located outside the firstprotruding portion in the widthwise direction and is narrower in widththan the first protruding portion and the second protruding portion. 8.The heat exchanger according to claim 6, wherein the first projection islocated at a position that is more distant from the third protrudingportion than the second projection in the widthwise direction.
 9. Arefrigeration cycle apparatus comprising: the heat exchanger accordingto claim 1; and a refrigerant circulation device, the refrigerantcirculation device being configured to circulate refrigerant forperforming heat exchange with air in the heat exchanger.
 10. A heatexchanger comprising: a fin extending in a widthwise direction andextending in a longitudinal direction crossing the widthwise direction;and a heat transfer tube passing through the fin, the fin having aplurality of through holes arranged in the longitudinal direction, theheat transfer tube being inserted in the plurality of through holes, thefin comprising a planar portion, and a plurality of first protrudingportions and a plurality of second protruding portions that protrudefrom the planar portion, the plurality of first protruding portionscomprising a first projection located between corresponding throughholes of the plurality of through holes and curved downward in thelongitudinal direction, and a second projection located betweencorresponding through holes of the plurality of through holes and curvedupward in the longitudinal direction, and each of the plurality ofsecond protruding portions being located between a corresponding one ofthe plurality of first protruding portions and a corresponding one ofthe plurality of through holes.
 11. The heat exchanger according toclaim 10, wherein each of the plurality of second protruding portionssurrounds the corresponding through hole.
 12. The heat exchangeraccording to claim 10, wherein a vertex of the first projection and avertex of the second projection are located at the same position in thewidthwise direction.